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25238 TPMT Enzyme, Prometheus (3320)

TPMT Enzyme, Prometheus (3320)
Test Code: ENZACSO
Synonyms/Keywords
​ENZACT
Useful For

​PROMETHEUS TPMT Enzyme testing provides a quantitative analysis of a patient's thiopurine methyltransferase (TPMT) enzyme activity level. Because each patient metabolizes thiopurines differently, the efficacy and toxicity of thiopurines can vary widely from patient to patient. Knowledge of the TPMT enzyme phenotype may: reduce time to response, allow physicians to individualize dosing, identify patients in whom thiopurine therapy should be avoided and help reduce the risk of leukopenia.

Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No Whole Blood EDTA Lavender Top Tube (LTT)​ ​ ​5.0 mL ​
Specimen Stability Information
Specimen Type Temperature Time​
Whole Blood ​ ​Refrigerate ​8 days
​Ambient ​24 hours
Rejection Criteria
Frozen samples
​Samples other than EDTA whole blood
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Prometheus Labs Monday through Friday​ 3 days
Enzymatic and HPLC​
Reference Lab
Prometheus Biosciences
Test Information
​TPMT enzyme testing provides a qualitative analysis of patient's thiopurine methyltransferase (TPMT) enzyme activity level. Because each patient metabolizes thipurines differently; the efficacy and toxicity can differ from patient to patient. Knowledge of the TPMT phenotype helps reduce response time, allows provider to provide individual dosing and help identify patients where thiopurine treatment should be avoided.
Reference Range Information
Interpretive report
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82542​ ​ ​1 Qnt HPLC for 6-methyl-thiguanine ​
​82657 ​ ​1 ​TPMP Metabolite enzyme activity in peripheral RBC ​
Synonyms/Keywords
​ENZACT
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No Whole Blood EDTA Lavender Top Tube (LTT)​ ​ ​5.0 mL ​
Specimen Stability Information
Specimen Type Temperature Time​
Whole Blood ​ ​Refrigerate ​8 days
​Ambient ​24 hours
Rejection Criteria
Frozen samples
​Samples other than EDTA whole blood
Useful For

​PROMETHEUS TPMT Enzyme testing provides a quantitative analysis of a patient's thiopurine methyltransferase (TPMT) enzyme activity level. Because each patient metabolizes thiopurines differently, the efficacy and toxicity of thiopurines can vary widely from patient to patient. Knowledge of the TPMT enzyme phenotype may: reduce time to response, allow physicians to individualize dosing, identify patients in whom thiopurine therapy should be avoided and help reduce the risk of leukopenia.

Reference Range Information
Interpretive report
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Prometheus Labs Monday through Friday​ 3 days
Enzymatic and HPLC​
Reference Lab
Prometheus Biosciences
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82542​ ​ ​1 Qnt HPLC for 6-methyl-thiguanine ​
​82657 ​ ​1 ​TPMP Metabolite enzyme activity in peripheral RBC ​
For most current information refer to the Marshfield Laboratory online reference manual.